Pushing the Boundaries of Quantum Information: The QINF Project

Current developments in quantum computing are based on qubits, or quantum bits, which are units of information encoded in quantum systems such as photons or ions. Generally, this involves manipulating the internal states of these systems (the polarization of photons or the energy levels of ions, for example) in order to perform computational operations. But what if there were another way to create quantum bits, one that instead uses the fundamental properties of a type of particle known as fermions? This is the goal of Marc Olivier Renou’s project, QINF (Fundamental Laws Ruling Quantum Information: Bits, Qubits, and Fermionic Bits in Networks).

Using the Properties of Fermions

In quantum physics, there are two main families of particles: fermions (such as electrons) and bosons (such as photons). They differ in that they obey different statistical laws that describe their collective behavior. Thus, two identical fermions can never occupy the same quantum state simultaneously. This is the Pauli exclusion principle, which explains the cohesion of matter and is mathematically represented by a rule known as “anticommutation.” In contrast, bosons can accumulate, creating exotic states such as superfluidity or Bose-Einstein condensation.

By encoding information in the presence or absence of a fermion, to form a fermionic bit, or febit, Marc Olivier Renou and his team aim to demonstrate that it is possible to perform tasks in quantum networks that would be impossible with traditional qubits.

New behaviors that would defy current theory

This conceptual breakthrough is inspired by the work of physicist John Bell and his theorem, which states that certain quantum experiments cannot be explained by classical theories, paving the way for Alain Aspect’s experiments on the phenomenon of entanglement. Similarly, QINF seeks to prove that certain behaviors of fermions in quantum networks cannot be reproduced by the standard theory of quantum information.

Preliminary theoretical results (1) indicate that, in certain networks, fermions could perform tasks that are impossible to reproduce with bosons. This discovery could revolutionize the way we conceive of quantum communication systems.

(1) M. Moradi et al., « Fermions are fundamentally more nonlocal than Bosons », arXiv:2606.12363 (2026)

*CPHT: a joint research unit CNRS, École Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France

*LIX: a joint research unit CNRS, École Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France